Representing Hybrid Object:
Hybrid objects can be transformed into relational
database design using both the combination techniques, of composite and compound
objects. The hybrid objects are converted into relational database design as:
- Create a relation for each object (such as
for parent and child).
- Create a separate relation for each
multi-valued attribute to store multi-values.
- Place the key of the parent relation in the
child relations as foreign key.
Example:
For example, the EMPLOYEE object diagram is given
below that contains one multi-valued group attribute 'Education' and one object
attribute 'DEPARTMENT'.
The above objects are represented into relations
as:
EMPLOYEE (EmpID, Name)
EDUCATION (Degree, Exam-Board, Marks, EmpID)
DEPARTMENT (Dept-ID, NAME, EmpID)
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